Update paper-toggle-button to 0.5.4

Update paper-toggle-button to 0.5.4

The latest <paper-toggle-button> matches the Material Design spec. The
MD-Settings page will make use of this button in a follow-up CL.

Since paper-toggle-button isn't currently used in Chromium there shouldn't
be any side effects for this change.

R=rsadam@chromium.org

Committed: https://crrev.com/853f543227467d80c2abfd1b65536c917683698d
Cr-Commit-Position: refs/heads/master@{#315078}

[rsadam, 2015-02-06 18:00:25]

lgtm

[michaelpg, 2015-02-06 18:39:11]

The CQ bit was checked by michaelpg@chromium.org

[commit-bot: I haz the power, 2015-02-06 18:39:44]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/899383002/1

[commit-bot: I haz the power, 2015-02-06 19:00:07]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-06 19:00:37]

Patchset 1 (id:??) landed as
https://crrev.com/853f543227467d80c2abfd1b65536c917683698d
Cr-Commit-Position: refs/heads/master@{#315078}